It is widely known to use nitric oxide in a variety of applications, for example as intermediate in the Ostwald process for the synthesis of nitric acid from ammonia. Additionally, several therapeutic applications are known.
As an example, nitric oxide is used by the endothelium of blood vessels to signal the surrounding smooth muscle to relax, thus resulting in widening the blood vessels and therefore increasing blood flow. This leads to nitric oxide being particularly applicable for blood pressure disease. However, many comparable or other applications are known for the use of nitric oxide. Exemplary applications for nitric oxide are for improving lung function and for treating or preventing bronchoconstriction or reversible pulmonary vasoconstriction, etc, for treating or preventing arterial restenosis resulting from excessive intimal hyperplasia in mammal, for Treatment of infected tissue e.g. to kill bacteria involving topical delivery of a source of nitric oxide containing gas to a skin surface containing infected tissue. One of the most famous applications of nitric oxide, however, is the administration for patients having the Persistent Pulmonary Hypertension (PPHN).
Nitric oxide may be administered in several ways. It is known to provide nitric oxide containing gases in gas cylinders. However, the handling and storage of the latter is complex with respect to safety measures. Furthermore, with respect to therapeutic applications, the stored gases have to comply with highly demanding requirements. It is thus much more advantageous to use an on-demand administration. This enables nitric oxide being generated directly before use and thus avoiding the safety and storage problems. Such an on-demand administration is very well suitable especially for home care applications. For enabling home care applications of nitric oxide, a mobile generation of nitric oxide is most favorable.
Methods are known to generate nitric oxide, including mobile nitric oxide generation. For example, it is known to generate nitric oxide by an electric gas discharge using only air and a source of electricity. This state of the art may be used exemplarily in medical or urgent care facilities for delivering a therapeutically-effective concentration of nitric oxide mixed with other gases to a specific organ of a human body.
The major drawback of the methods known from the state of the art is the considerable formation of nitrogen oxides in higher oxidized states. As an example, nitrogen dioxide is formed. Due to the high toxicity of these nitrogen oxides in higher oxidation states, especially nitrogen dioxide, the generated gas mixture cannot be used directly, but further purification steps are required instead.